Circular saw sharpening machine



Aug. 8, 1950 w. T. HARRELL CIRCULAR SAW SHARPENING MACHINE Filed Jan. 5, 1948 3 Sheets-Sheet 1 Fig.

m 5 El I d7 Inventar Will/hm 7'. Harrell, Deceased Rut/1 ll. Harrell,

Adm/n/sfrafr/Lv Of The Estate 8, 1950 w. T. HARRELL 2,517,873

CIRCULAR SAW SHARPENING MACHINE Filed Jan. 5, 1948 5 Sheets-Sheet 2 F/g.3. 24 Fig.4.

I n ventor Will/hm 7'. Harrell, Deceased Ruth M. .Harre/l,

Adm/n/s/rafn'x Of The E state Aug. 8, 1950 Filed Jan. 5, 1948 W. T. HARRELL CIRCULAR SAW SHARPENING MACHINE 3 Sheets-Sheet 3 V I ;i Fig. 6. l5 L, /4

Inventor William T. Harrell, Deceased Ruth M Harrell,

Admin/strain Of The E state Patented Aug. 8, 1950 .WilliamlTCHarriSll, fdeceased, late, of.H igh Point, 'N. 0., .by Ruthvfiflarrell, administratrixgHigh ,TointlN. o.

Applicationdanuary 5, 1948,. SerialNo.,518

"4 Claims.

.eThis' invention relatesrto. improvements .incir- .cular sawsharpening machinesandthe primary .object; ;of-. .the invention is to provideaaivery {simple and efficientmachine-which isiadapted to rap- -idl n and accurately grind :circular .saws vto. sharpen the same.

' Another-obj ect .of..-.the. invention is .to provide. a rmachine of theabove kind whichembodies anovel.- and practical combination and 1 arrangement of parts-and devicesawhich afiorda verypractiveal machine =-organization-which .is. easy and ..conrvenient tense and control. I

The exact" nature .-of 1 the present invention,-- as well :as other :objects and features.thereof,. .will

become apparent. from the following description #when considered in. connection with the accompanying drawings, in which:

Figure 1' is a. front elevational: view 'of .a circu- --lar saw: sharpening machine; constructed .-:in= I accordancewiththe present invention; 7

Figure 2 is a top plan view thereof;

Figurem3 is -.a--side-::elevationalviewrlookingtoward the left of: Figure 1;:part-1y brokenlaway'and :in section;

IFigure. ii-is a vertical section :takensubstantiallyon line d d'ofiigure 1;

vFigure 5-.1'S ;a horizontal section:,:taken substantiallyon'line 55 of Figure l Figure 6 :is a central vertical sectionall-view through the' saw and its mounting-means,- taken on line 6-45 of-Figure 1; v 1

- Figure T is afragmentary. horizontal section through the saw and its mounting means rtaken online l--'I-of Eigure 1;

-Eigure .8, is a; fragmentary detail view, partly .-broken..away and in section showing. .the .pivotal -.-mounting of the. saw. advancingpawl.

. Referring :in-tdetail to...the.drawings; the; .present machine includes a asuitable table WT ,composed ofaa frame 5 and a-tabletop ,6,.said frame Tincluding corner supporting .legs. I .having .wheels .8.-.at .theirr-lower ends to facilitate imovement. f .thelmachine from oneplacelto another.

. :Mea ns :is provided ;for removably rotatably .mounting a circularwsaw's-on andparallel with wthefrontof the table T-so-as toproject above-the .itopfi-ofathe latter. This cmeanseincludes averticalrbar 9 rigidly secured ongthe :frontpf .the. table .snean-one side -of :the latter and provided-withla fcentral alongitudinal elongated slot- I 0,; a similar ;bar. 4 lxdisposed :in front of-iand parallel withthe vbara-9:.and:having arlongitudinal; elongated slot 5| 2. II-the lower 1 end: of: bar; I la is rearwardlyiofisetx and looltedzwithzthevlower ,rendxofzbar 9 toia.the: frame-:5

Jae-sat n. 11A PiVOt aI'lGII mam m moml 4-; extends 'throughtheslote' Ill. and I2,.and has the sawS removably rotatably disposed, thereon. The ;upperwendpf bar' I I, is lightly frictionally. engaged with thesaw. to prevent lateral flexing, and vibration of .the latter, by adjustment of a nut I5 threaded ,on the pivot bolt I4. It will be'noted that 'the bars ,9 and, I l, .pivot .bolt I4. and nut I5 .,provide .a clamp andjournal for the saw, and in .practiceJthe. adjustment ofthe nutiI5 is such that forcible turning of ..'the saw is permitted .while vLthesame is braced against. undue lateral vibration. It will be seen that vertical adjust- ...mentvoflthepivot boltv I4 in, the.slots .Ill and I2 provides for adaptingthe machine to sawsof different'diameters. The machine also includes a grinder composedgof an electric motor lfi having an elongated rotarypower shaft I'I and a grinding wheel I8.secured.on the outerend of saidpower shaft. Meanspjs provided which rockably mounts the grinder on the top and at the front of the table. The latter. means includes a, shaft I9 having its ends secured in brackets 20. fastened upon the table. topJ.-6 .near one end andat the frontuand -.back of. theclatter. .L Pivoted on the front end of .shaftlflisaplatform 2I on which the motor I6 is fastened, Anarm 22 is fixed to the platform 2I and has. alateral free end portion23 provided .With.. a..bearing 24in which the power shaft. I? is journaled adjacentthe grindingwheeLIB. vThe aarm, 2271s rbraced by .a. diagonal brace; bar. 25 attached.- at=one end tothe arm 22 and atits other end to .a collar 26r-rotatable on the shaft- 59 ,ad-

. rjac.en titherearbracket 20.

A -driven; shaft 21 lis horizontally. journaled on and.-be1ow,;the top oithe. table at a point below the-saw and so asto; extend from front to rear -:of -;said table. JI-his shaft is drivenby an electric motor-.48; mounted in. the frame adjacent said shaft-and operatively connected to ,the latter :through; arspesdreductiou; gearing. Asshown, thespeedzreductiona gearing includes a .countershaftkzZ 9c journa1ed in the. frame lbeneath the taublentopdandpaboveshaft;21, .a power transmis- Means operatively connects the shaft 21 to the grinder for intermittently rocking the latter to alternatively move the grinding wheel I8 downwardly into and upwardly out of engagement with a tooth of the saw. For this purpose, a push rod 31 is vertically slidable through the top of the table and pivotally connected at its upper end as at 38 to the arm 22, the lower end of rod 31 bearing against a cam 39 secured on shaft 21. As indicated generally at 4|], the rod 31' is adjustable in length so as to properly set the grinding wheel I8 with respect to saws of different diameters.

Saw advancing means is provided including a pawl 4| operatively connected to the shaft 21 and engageable with a tooth of the saw for automatically turning and thereby advancing the latter the distance of one tooth each time the grinding wheel I8 is moved upwardly out of engagement with the saw. As shown, the pawl 4| is pivoted at 42 to the free end of a lever 43 which is pivoted at its upper end to the table frame as at 44. The lever 43 is, in turn, connected intermediate its ends by a pivot 45 to the upper end of a push rod 46 which bears at its lower end on a second cam 41 secured on shaft 21. The rod 46 is made adjustable in length as indicated at 48 so as to vary the stroke of pawl 4| in accordance with the different sizes of teeth on different types a set screw 5| so that the position of the pawl relative to lever 43 may be adjusted.

The motor I6 may be convenientl thrown into and out of operation by the actuation of a manually operable switch 52 mounted in the frame 5 directly beneath the tabl top 6 and at the front of the table. In a like manner, the motor 28 may be thrown into and out of operation by the actuation of another manually operable switch 53 mounted in and at the front of the frame between the motor 28 and shaft 21.

Means is provided for conducting the grindings from the grinding wheel and saw as the grinding operation proceeds, such means including a vertical conduit 54 extending through the table top 6 and depending to a point adjacent the bottom of the table, said conduit being provided at its upper end with an elbow shaped intake funnel 55 disposed adjacent and at the rear of the lower portion of grinding wheel I8 and the upper portion of the saw. As the grinding wheel I8 is driven in a counter-clockwise direction as viewed in Figure 3, it acts to project the grindings rearwardly into the intake funnel 55 so that such grindings may fall by gravit through the conduit '54 onto the floor or into a suitable receptacle disposed therebeneath.

By removing the nut I5 from pivot bolt l4, the bar I may be sprung away from the bar 9, and the pivot bolt I4 may be passed through the central opening of saw S with the latter positioned between the upper end portions of said bars 9 and I I as shown in Figure 6. The nut I5 is then threaded onto pivot bolt I4 and lightly tightened so that the saw is efiectively braced between the upper ends of the bars 9 and I I, although insufficient gripping action is had on the saw to prevent its forcible rotation on the pivot bolt I4 by the action of pawl 4|. The motors I6 and 28 are then thrown into operation by actuation of switches 52 and 53. Cam 39 then turns to permit rod 31 to lower 50 that the grinder will tilt by gravity in the direction wherein grinding wheel I8 moves downwardly into engagement with a tooth of the saw. The grinding wheel remains for a short time in this engaged position and thereby grinds and sharpens the tooth, whereupon the cam 39 moves rod 31 upwardly and tilts the grinder so that its grinding wheel I8 is moved upwardly out of engagement with the sharpened saw tooth. At this time, cam 41 actuates rod 46 so as to move pawl 4| upwardly and, through engagement of said pawl with a tooth of the saw, to turn the latter the distance of one tooth so that the next tooth of the saw is brought into position for being sharpened. Cam 41 then allows rod 46 and pawl 4| to lower so that the pawl is brought into position for the next saw advancing operation of said pawl, and just prior to this time, the cam 39 permits lowering of rod 31 so that the grinder tilts by gravity to allow grinding wheel I-8 to engage the succeeding tooth which has been brought into position for being sharpened. The above described cycle of operation is repeated until all teeth of the saw have been sharpened, whereupon the motors I6 and 28 are thrown out of operation and the saw is removed. After the saw has been mounted in place and the position of the grinding wheel and the saw advancing pawl have been properly adjusted, the machine only requires the attention of actuating the switches 52 and 53 to throw the motors I6 and 28 into and out of operation.

From the foregoing, it is believed that the construction, operation and advantages of the present invention will be readily understood and appreciated by those skilled in the art. It will be seen that the machine comprises a very practical organization and arrangement of parts and devices whereby the machine may be readily and cheaply constructed and conveniently controlled or used. In use, the machine has been found very efficient and. of such a character as to meet with the requirements for successful commercial use. Modifications and changes in details of construction are contemplated, such as fairly fall within the scope of the invention as claimed.

Having described the invention, what is claimed as new is:

1. A circular saw sharpening machine comprising a table having a horizontal top, means to removably and rotatably mount a circular saw in a vertical position at and parallel with the front of said table so as to project above the top of said table near one side of the latter, a grinder including an electric motor having an elongated rotary power shaft and a grinding wheel secured on the outer end of said power shaft, means rockably mounting the motor of said grinder on the top and at the front of said table so that the grinder is bodily tiltable about a horizontal axis extending from front to rear of the table near the other side of the latter and so that the power shaft thereof projects toward said one side of said table, a motor driven shaft journaled on and below the top of said table and below and to one side of the saw, means operatively connecting said shaft to the grinder mounting means for intermittently rocking the latter grinder to alternately move the grinding wheel downwardly into and upwardly out of. engagement with a tooth of the saw, and

saw advancing means including a pawl operatively connected to said motor driven shaft and engageable with a tooth of the saw at said one side of the latter for automatically turning and thereby advancing said saw the distance of one tooth each time the grinding wheel is moved out of engagement with a tooth of the saw.

2. A circular saw sharpening machine comprising a, table having a horizontal top, a vertical saw clamp mounted at the front and near one side of the table and including a clamping bolt on which the saw may be rotatably mounted, said clamping bolt being vertically adjustable to accommodate in a predetermined position saws of various diameters, a shaft mounted on the top of the table near the other side of the latter and extending from front to rear of the table top, a platform pivoted on said shaft and having an arm projecting toward the saw, a grinder including a motor fixed on said platform and having an elongated, shaft journaled in the arm, and a grinding wheel on the free end of said shaft, said platform and motor being disposed at the front of the table, a cam shaft journaled on the table beneath the table top, a pair of cams secured on said cam shaft, a push rod actuated by one of said cams and connected to said arm for intermittently rocking the grinder to move the grinding wheel upwardly out of engagement with a tooth of the saw and to allow downward movement of the grinding wheel into engagement with a tooth of the saw, a pawl engageable with a tooth of the saw at one side of the latter and vertically movable relative to the table, and means including a push rod actuated by the other cam and operatively connected to the pawl for actuating the latter so as to turn the saw the distance of a tooth each time the grinding bination with means to conduct grindings from the grinding Wheel and saw including a vertical conduit extending through the top of the table and depending to a point adjacent the bottom of the latter, and an elbow-shaped intake hood on the upper end of said conduit located at the rear side of the grinding wheel and saw.

RUTH V. HARRELL, Administratrix of the Estate of William T.

Harrell, Deceased.

REFERENCES CITED The following references are of record in the file of this patent! UNITED STATES PATENTS Number Name Date 359,133 C ovel Mar. 8, 1887 458,205 Wheeler Aug. 25, 1891 1,501,564 Lifflander July 15, 1924-. 1,530,378 Lanfranchi Mar. 17, 1925 1,780,886 Pribnow et al. Nov. 4, 1930 1,832,878 Porter Nov. 24, 1931 2,146,686 Raxll Feb. '7, 1939 2,329,879 Christy et al. Sept. 21, 1943 2,334,136 Underwood Nov. 9, 1943 

